Propeller



m. 28, 1943. M. T. ADAMTCHIK 2,337,861

PROPELLER Filed April 25, 1942 5 Sheets-Sheet 1 INVENTOR yqlch qelThuddws Adomrc hik A44 ATTORNEY DH; 28,, 1943. M, ADAMTCHIK 2337 861PROPELLER Filed April 25, 1942 5 Sheets-Sheet 2 M. T. ADAMTCHIK 2,337,

PROPELLER Filed April 25, .1942 5 Sheets-Sheet 3 Michael Thadd'wsAdonrficHK M. T. ADAMTCHIK PROPELLER Filed April 25, 1.942 5Sheets-Sheet 4 M {chad Thodehb 5 Admwckik \NVEN g @m. 28, 1943. M, T.ADAMTCHlK PROPELLER Filed April 25, 1942 5 Sheets-Sheet 5 \m m M LI mm M.T .N A L WW m m QM Q mama Dec. 1943 U'NirEo STATES PATENT orgiesPROPELLER Michael Thaddius Adamtchik, Saltdean, England, assignor ofone-half to James Russell Kennedy, Belsize Park, London, EnglandApplication April 25, 1942, Serial No. 440,498 In Great Britain February4, 1941 6 Claims.

' used in conjunction with a screw propeller enables the latter.to'operate at its maximum emciency throughout its entire range ofoperation.

In order toachieve this result various arrangements have been usedhitherto. One arrangement, generally known as a variable pitchpropeller, is based on changing the ratio 'of the mean geometrical pitchof the propeller relatively to its diameter.- This arrangement, however,has the disadvantage that it is complicated, by reason of the necessityof I pivoting the blades under a load produced by the centrifugal forceacting on the blades, an excessive effort is required to pivot theblades, and the efficiency. is low when the ratio of the geometricalpitch to the diameter of the blade is small.

Another known method is to provide the. screw propeller withflxed oradjustable vanes for imparting to the ingoing fluid a counterswirlsubstantially in excess to the circumferential drag of the impeller.Under these conditions the coefllcient of the load of a given propellerincreases by reason of the increase of the rotational momentum. Howeverthe conditions only obtain at the commencement of the propelleroperation and no provision is made for obtaining suitable conditions atcruising or maximum speeds.

In a thirdknown arrangement adjustable inlet guide vanes of symmetricalaerofoil section The real purpose of inlet guide vanes in an'aerodynamic sense is to produce an alteration in the circulation of thefluid around the pro-.

peller blades, the circulation" being the expression IV cos 0 ds, whereV=the velocity around an aerofoil; 0=the angle between the path aroundthe aerofoil and the path of movement of the air, andds=an element ofthe path.

It is known that the blades of a screw propeller may be designed eitherfor aconstant circulation or for a variable "circulation."

Investigations have shown that adjustable or fixed inlet guide vanes atpresent in use are not capable of producing variations in thecirculation" which are comparable with those produced by variable pitchpropellers'as-only a small increase in the circulation is obtained bythe use of negative angles of pivoting .of about 10 to 15, the"circulation decreasing'when the angle of pivoting is increased beyondthese values. This is due to the use of symmetrical aerofoils whichproduce a variation of the circulation which is not directlyproportional along the blade. g

It has now been foundthat in order to obtain the maximum efliciency atevery position of the inlet guide vanes it is necessary to produce anincrement in the circulationfi either negative or positive, which isproportional to the basic variations in the circulation along the blade.This implies the use of stationary inlet guide vanes having a variablepitch and a variable camber of aerofoil section. V

The present invention obviates the disadvantages of the knownarrangements referred to above. 4

According to the present invention a number of flexible preferablyhollow vanes or variable pitch and variable camber arearranged to bepivotally mounted in a stationary position, relatively to a screwpropeller, so as to enable them to be set at a positive or negativeangle.- The setting angle is preferably variable to a maximum amount of:20% from the neutral position for high efllciency. When efllciency isnot of primary importance the angle of curvature may be greater. Thevanes may be constructed of stainless sheet steel of high elasticity orof'other suitable material, for example canvas. The vanes are preferablyconstructed in sections arranged in close fitting overlappingrelationship along the length of the vane so as to assume the variousrequired positions. 1

Preferably the number of vanes is greater by one than the number ofpropeller blades so as to to the circulation avoid sound interferencebetween the blades and vanes. The vanes are preferably mounted be-'tween a central hub and an outer casing member so as to form aself-contained unit applicable to any type or engine in a stationarymanner. Means are also provided for varying the position of the vanessimultaneously.

The invention will now be described by way of example to theaccompanying drawings, wherein:

Figure 1 is a partial sectional elevation on the line I-I of Figure 2, I

Figure 2 is an end elevation of a screw propeller provided with aregulating device according to the invention,

Fig. 3 shows to a larger scale a sectional plan of a vane with itsgovernor plate in the neutral position.

Figs. 4 and 5 show similar views to Fig. 3 with the governor plate inits rearward and forward positions respectively.

Fig. 6 shows a diagrammatic plan view to the same scale as Fig. 1indicating the position of the upper end of the vane with the governorplate in the positions shown in Figs. 3 to 4,

Figure 7 is an end elevation of a screw imp ller or pump,

Figure 8 is a section on ure 7,

Figure 9 is a partial section on the line 9-9 of Figure 7,

Figures 10 and 11 show details.

Referring first to Figures 1 to 6 showing an example of construction asapplied to an aircraft engine, the apparatus consists of a centralstreamlined boss I which is shaped to correspond with the adjacentaircraft or engin'e frame 2 to which it is to be attached. Arrangedinspaced relation to the boss I is a circular outer casing member 3 ofstreamline shape which may extend over the propeller blades 4 withslight clearance 5. The outer casing member 3 is preferably of materialsold under the registered trade-mark Duralumin and in cross sectionresembles a. hollow aerofoil of which the outer side 6 is formed ofsheeting.

In the hub I and casing 3 there are mounted uniformly spaced shafts I onwhich sleeves 8 are rotatably mounted. On each of these sleeves 8 ismounted at about its leading edge III a hollow vane 9 of aerofoil crosssection. These vanes are of stainless steel of high elasticity or otherstrong material. Preferably each vane 9 consists of a number of sectionsarranged side by side along the length of the vane and slightlyoverlapping one another.

Intermediate the leading and trailing edges III, II of each vane 9,preferably nearer to the trailing edge II, a second shaft I2 passesthrough the vane 9 parallel to the first shaft I. Around the shaft I2 isfitted a sleeve I8.

Around the boss I there is mounted concentrically a casing member I3which is secured positively to the boss I. The shafts 'I, I2 and sleeves8 and I8, pass through thi casing member I3 whilst the first shaft 1 issecured to the boss I. The shaft I2, with its sleeve I8, passes througha suitably shaped slot in the casing I3. To the lower end of the sleeve8, inside the space between the casing member I3 and the boss I, thereis secured a lever I4 having a short slot the line 88 of- Fig- I5 (Figs.3, 4 and 5) for the reception of the lower end of the second shaft I2and its sleeve I8. Between the two shafts I, I2, the lever I4 carries aguide pin I8, whilst a guide pin I1 is connected freely to the lower endof the sleeve I8 above the lever I4. To the lower end of the sleeve I8is secured a guide pin I9. The guide pins I6, I9, I'I engage with slots20, 2|, 22 in a governor plate 23 (Figs. 3, 4, 5) slidably mounted onthe boss I. The guide pin I6 on the lever I4 engages with the slot 20,the guide pin I9 on the sleeve I8 with the slot 22 and the guide pin I9with the slot 2I.

The slots 20, 2I, 22 in the governor plate 23 are so arranged that whenthe governor plate 23 is moved from the neutral position shown in Fig. 3into the position shown in Fig. 4, the vane 9 is moved from the positionshown in Fig. 3 to that shown in Fig. 4.

During this movement of the governor plate 23 the pin I6 moves along theslot 20 about the shaft 1 with the axis of this shaft as centre ofrotation. This rotary movement of the pin I6 is followed by the leverI4. The slot 2I is made of such a'shape that the pin I9 at the end ofthe sleeve I8 is caused to lag relatively to the pin I8 so that thesleeve I8 and shaft I2 are tilted from the lower end thereof outwardly,that is to say towards the bottom of Fig. 4, the slot I5 being ofsufiicient size to permit of this tilting.

The tilting movement of the shaft I2 and sleeve I8 is assisted by theaction of the pin H, which turns on the sleeve I8, whilst moving alongits slot 22 which latter is so arranged as to cause the pin II to movein advance of the pin I9.

By this arrangement of the pins I8, I9, I! and slots 28, 2I and 22 thepitch and camber of the vane 9 are varied in one direction.

By moving the governor plate 23 from the position shown in Fig. 3 intothe position shown in Fig. 5 the pins IS, I9, I! and the slots 20, 2Iand 22 serve to vary the pitch and camber of the vane 9 in the oppositedirection to that described with reference to Figs. 3 and 4.

Fig. 6 shows the outer end of the vane in the full line positionindicated at 9 when the root end of the vane is in the position shown inFig. 3, in the chain dotted position 9' when the root end of the vane isin the position shown in Fig. 4, and in the chain dotted position 9"when the root end of the vane is in the position hown in Fig. 5.

By means of the arrangement described with reference to Figs. 4 to 6 thecurvature and geometrical pitch of the vanes can be varied as may bedevised so as to vary the circulation.

The governor plate 23 is guided during its movement by a block 23 whichengages with a slot 23" in the forward end of the governor plate 23.

The governor plate 23 can be moved manually, hydraulically,mechanically, pneumatically, electrically or in any other suitablemanner.

As will be appreciated a separate governor plate 23 is provided for eachvane 9, the separate plates 23 being coupled together in any suitablemanner so as to operate in synchronism.

The plate 23 is preferably brought into the neutral position (Fig. 3)for a cruising speed which determines the most suitable ratio of thegeometrical pitch to the diameter of the propeller for the design of thelatter.

For taking off there are used the negative angles of pivoting and formaximum speed the positive angles of pivoting.

When the governor plate 23 is in the neutral position the centres of theguide pins I6, I9, II are all in alignment with the central plane of thevane 9 as shown in Fig. 3.

By making the hub I hollow the apparatus can be arranged in front of ahollow propeller hub 24 without interfering with firing through thepropeller hub 24. i

As the huh I is stationary the application of de-icing arrangements isfacihtated.

Provision may also be made for circulating heated air through the shaftsI, I2, which are hollow, and shroud I3 for preventing the formation ofice.

Referring now to Figures 7 to 9 which show the invention applied to animpeller fan or pump,

ing 43.

the mechanism for varying the pitch and camber of the vanes is mountedinside a casing 25 connected by radial webs 26 to an outer housing 21.As the housing 27 is not spaced a considerable distance from the casing25 a shaft 28, to which a vane 29 is secured near its leading edge,passes at one end through the casing 25 and a frame member 30, securedto the casing 25, whilst its other end is free.

Near its trailing edge the vane 29 is secured to a shaft 3| provided atits inner end with a ball 32 engaging with a corresponding seating atthe inner end of a suitably shaped slot, in the casing 25. From thebal132 there extends inwardly a spindle 33 which passes through anarcuate slot 34 in the frame member 30.

To the inner end of the shaft 28, inside the frame member 30, is secureda lever 35 which is provided with a slot 36 with which the inner end ofthe spindle 33 engages.

To the shaft 28 is also secured an arm 31, whilst an arm 38 is securedto the spindle 33. The arms 31, 38 are connected together by a link 39which engages with the arms by ball joints.

The levers 35 for actuating the separate vanes 29 are each provided witha pin 40. These pins 40 engage with a floating ring 4| which can beactuated manually, hydraulically, mechanically,

pneumatically, electrically or in any other suit-- able manner. By therotation of the ring M in a clockwise direction the pitch and camber ofthe vanes 29 are varied whilst the vane is also twisted into an aerofoilof different curvature.

Thus assuming that the parts are in the position shown in Figs. 8 and 9and the ring 4i is turned in a clockwise direction the lever 35 and thusalso the shaft 28 are rocked in an anticlockwise direction Fig. 9. Theshaft 3| thus moves in a direction through the drawing, whilst thespindle 33 moves away from the drawing (Fig. 8) (upwardly Fig. 9) whilstmoving along the slot 36 in the lever 35. As a result-of the connectionof the arms 31, 38 by. the link 39 the vane is also twisted.

With the arrangement shown in Figs. 8 and 9 the pitch of the vane 29 canonly be varied in the'direction as above described, the vane 29 assumingsubstantially the position of the vane 3 as above described withreference to Figs. and 6. a

The impeller is indicated at 42 whilst its driving motor is indicated at43.

If desired -a further set of vanes may be arranged behind the impeller42.

Brackets 44 serve to support the motor cas- As shown in Figure lfl avane 45 is hollow whilst the portions of theshafts 46, 41- which passtherethrough are of oval or elliptical cross section.

In Figure 11 a vane 48 is formed of a single layer of material of whichone end is looped 1. In apparatus for the purpose described, thecombination with a screw propeller of a plurality of flexible vanes,each of said vanes having a leading edge and a trailing edge, aplurality of shafts mounted in a stationary position relatively to saidpropeller, one shaft being associated with each vane, each of saidshafts extending parallel to the leading edge of its corresponding vaneand being located towards said leading edge, a plurality of a secondseries of shafts'said second series of shafts being associated one witheach of said vanes and being located parallel to and towards thetrailing'edge of its associated vane, and mechanism operativelyassociated with said second series of shafts, said mechanism serving torock the said second series of shafts relatively to the first series ofshafts so as to vary the camber of said vanes at their trailing edge.

2. In apparatus for the purpose described, the combination with a screwpropeller of a plurality of flexible vanes, each of said vanes having aleading edge and a trailing edge, a plurality of shafts mounted in astationary position relatively to'said propeller, one shaft beingassociated with each vane, each of said shafts extending parallel to theleading edge of its corresponding vane and being located towards saidleading edge, mechanism operatively associated with all of said vanes,said mechanism serving to vary simultaneously the pitch and camber ofall the vanes at the same time at a positive or negative anglerelatively to said propeller, said mechanism including means fortwisting each of said vanes into an aerofoil of different curvature.

3. In apparatus for the purpose described, the combination with a screwpropeller of a plurality of flexible vanes, each of said vanes having aleading edge and a trailing edge, a plurality of shafts mounted in astationary position relatively to said propeller, one shaft beingassociated with each vane, each of said shafts extending parallel to theleading edge of its corresponding vane and being located towards saidleading edge, a second series of shafts, said second series of shaftspassing one through each of said vanes and being located parallel to andtowards the trailing edge of its associated vanes a plurality of slidingplates corresponding with the number of vanes, a plurality of sleeveslocated one around each of said shafts, a plurality of pairs of guidepins secured one pair to each sleeve surrounding the second series ofshafts, a plurality of levers mounted one on each sleeve surrounding thefirst series of shafts, a plurality of guide pins secured one to each ofsaid levers, each of said sliding plates having three slots therein, theslot nearest the leading edge being engaged by the guide pin on saidlever, whilst the other two slots are engaged by the pair of guide pinson the sleeve of the second series of shafts, each of said levers havinga transverse slot near its free end, said transverse slot being engagedby the sleeves of the second series of shafts, the said sliding plateswhen moved from a neutral position, in which the vanes are also in aneutral position, rocking the second series of shafts, relatively to thefirst series of shafts so as to vary the pitch and camber simultaneouslyof all the vanes, whilst at the same time also twisting the separatevanes into an aerofoil of different curvature.

4. In apparatus for the purpose described, the

combination with a screw propeller of a plurality shafts mounted in astationary position relative- 1y to said propeller, one shaft beingassociated with each vane, each of said shafts extending parallel to theleading edge of its corresponding vane and being located towards saidleading edge, a second series of shafts, said second series of shaftspassing one through each of said vanes and being located parallel to andtowards the trailing edge of its associated vane, a plurality of leversmounted one on each of said first mentioned shafts each of said levershaving a slot therein, a plurality of balls mounted one at the end ofeach of the shafts of the second series of shafts, seatings for saidballs, a plurality of spindles secured one to each of said balls, saidspindles engaging said slots, and mechanism operatively associated withsaid levers, the arrangement being such that when the levers areoperated the pitch and camber of all the vanes is varied simultaneously.

5. In apparatus for the purpose described, the combination with a screwpropeller of a plurality of flexible vanes, each of said vanes having aleading edge and a trailing edge, a plurality of shafts mounted in astationary position relatively to said propeller, one shaft beingassociated with each vane, each of said shafts extending parallel to theleading edge of its corresponding vane and being located towards saidleading edge, a plurality of a second series of shafts, said secondseries of shafts being associated one with each of said vanes and beinglocated parallel to and towards the trailing edge of its associatedvane, the portions of all of said shafts passing through said vanesbeing of elliptical cross section.

6. In apparatus for the purpose described, the combination with a screwpropeller of a plurality of flexible vanes, each of said vanes having aleading edge and a trailing edge, a plurality of shafts mounted in astationary position relatively to said propeller, one shaft beingassociated with each vane, each of said shafts extending parallel to theleading edge of its corresponding vane and being located towards saidleading edge, a plurality of a second series of shafts, said secondseries of shafts being associated one with each of said vanes and beinglocated parallel to and towards the trailing edge of its associatedvane, the portions of said first mentioned shafts being of ellipticalcross section, said vanes being of sheet material and havingtheir.leading edges looped around said elliptical portions, said second seriesof shafts being of as flat a section as possible and being secured tosaid vones towards their trailing edge.

MICHAEL THADDIU S ADAMTCHIK.

